diff --git a/src/browser/tests/document/query_selector.html b/src/browser/tests/document/query_selector.html
index 91675b82..96179ede 100644
--- a/src/browser/tests/document/query_selector.html
+++ b/src/browser/tests/document/query_selector.html
@@ -270,3 +270,27 @@
   testing.expectEqual('rect', document.querySelector('svg g rect').tagName);
 }
 </script>
+
+<script id=special>
+  testing.expectEqual(null, document.querySelector('\\'));
+
+  testing.expectEqual(null, document.querySelector('div\\'));
+  testing.expectEqual(null, document.querySelector('.test-class\\'));
+  testing.expectEqual(null, document.querySelector('#byId\\'));
+</script>
+
+<div class="café">Non-ASCII class 1</div>
+<div class="日本語">Non-ASCII class 2</div>
+<span id="niño">Non-ASCII ID 1</span>
+<p id="🎨">Non-ASCII ID 2</p>
+
+<script id=nonAsciiSelectors>
+  testing.expectEqual('Non-ASCII class 1', document.querySelector('.café').textContent);
+  testing.expectEqual('Non-ASCII class 2', document.querySelector('.日本語').textContent);
+
+  testing.expectEqual('Non-ASCII ID 1', document.querySelector('#niño').textContent);
+  testing.expectEqual('Non-ASCII ID 2', document.querySelector('#🎨').textContent);
+
+  testing.expectEqual('Non-ASCII class 1', document.querySelector('div.café').textContent);
+  testing.expectEqual('Non-ASCII ID 1', document.querySelector('span#niño').textContent);
+</script>
diff --git a/src/browser/webapi/selector/Parser.zig b/src/browser/webapi/selector/Parser.zig
index a594f66f..fbedf17f 100644
--- a/src/browser/webapi/selector/Parser.zig
+++ b/src/browser/webapi/selector/Parser.zig
@@ -237,8 +237,9 @@ fn parsePart(self: *Parser, arena: Allocator, page: *Page) !Part {
         },
         '[' => .{ .attribute = try self.attribute(arena, page) },
         ':' => .{ .pseudo_class = try self.pseudoClass(arena, page) },
-        'a'...'z', 'A'...'Z', '_' => blk: {
-            const tag_name = try self.tag();
+        'a'...'z', 'A'...'Z', '_', '\\', 0x80...0xFF => blk: {
+            // Use parseIdentifier for full escape support
+            const tag_name = try self.parseIdentifier(arena, error.InvalidTagSelector);
             if (tag_name.len > 256) {
                 return error.InvalidTagSelector;
             }